X-ray projection imaging or CT imaging provides a number of benefits, as is known in the art. CT requires acquiring projections or views from a multiplicity of angles around the object from which a tomographic image of structures within the object or patient is derived.
Since the beginning of CT, cardiac imaging has been a key technology driver. Multiple innovations have attempted to address high temporal resolution needed. Although current CT systems can image a cross-section of the heart in about 100 milliseconds, this may not be sufficiently fast for full diagnostic information.
Faster complete data acquisition sufficient for reconstruction of a tomographic image of a slice of interest are enabled through what is known in the art as “half-scan,” or “partial-scan” imaging, where projections are acquired for a particular slice to be imaged during a gantry rotation angle less than 360 degrees.
CT systems with a rotating gantry typically have only one radiation source; although at least one medical imaging system is commercially available with two radiation sources.
In the available medical imaging dual-source CT system, the two x-ray tubes are offset by an angle of about 95 degrees. In this system, however, the second imaging chain with a radiation source and a detector does not cover the full imaging field of view: the corresponding projections are truncated.
Security imaging, such as aviation security imaging, also requires very high scanning throughput, which is improved by high temporal resolution. Security CT systems with rotating gantries are available with two radiation sources: in one of these, the two sources are positioned as close as possible and power is pinged from one to the other at various kVp levels, tube current, and beam filtration, to acquire dual-energy projection data.
Other CT security systems use multiple sources arranged on a fixed gantry. This necessarily results in a relatively sparse sampling in the view-angle direction (also named the “projection angle direction”).